Every chess player has their own habits and views when it comes to training or chess in general. What might work for some strong players might be of no use for others and the other way around. You have to analyze your style of play and create your own training schedule that will help you improve your overall performance. However, while the percentage of hours invested in your training weighs most when it comes to seeing an increase in your rating, we believe that there are also other factors that influence it. Having a healthy and disciplined lifestyle is of great importance and will improve your overall performance in tournaments.
Here are some things chess masters do in order to prepare for tournaments and improve their play and might work for you as well.